The 240VAC usually comes from a single phase center tap transformer in a big can way up the power pole outside your house. It will almost certainly not pass powerline from 1 120VAC phase to the...

@Nik_Bcn Hi, I got 3 P9s for my son's house and had similar issues. I think the problem is that the powerline backhaul doesn't cross over from one 120VAC leg to the other in 240VAC service. Two of my...